1. Field of the Invention
The present invention provides a resin composition which is colorless under ambient visible light, develops a red color under irradiation of ultraviolet light, and is used for an ultraviolet luminescent screen.
2. Prior Art of the Invention
Luminescent screens prepared by use of luminescent inorganic compounds have been proposed in many patents, for example, Japanese Laid-Open Patents SHO 49-89688(1974), 49-122490(1974), 53-33986(1978), 55-149375(1980), 56-8485(1981) and 57-23676(1982).
Fluorescent materials used for these screens are inorganic ions or oxides and must be used in a turbid state because they have no transparency in the resin used in the luminescent screen. Consequently bright display cannot be obtained unless ultraviolet light for excitation irradiates the front face of the screen. However, front face irradiation has a high degree of risk of injuring eyes by reflected light. As a result, it has been strongly desired to develop a transparent resin screen which can be irradiated from the back.